08/21/2026
The Rio Grande Valley’s topography is extremely flat. To put it simply, imagine dumping thousands of gallons of water onto a flat surface and wondering why the water has nowhere to go. That, in a nutshell, is one of the fundamental drainage challenges facing Cameron County Drainage District No. 5, as well as other drainage districts, cities, and counties throughout the region.
Because of this flat terrain, we have to rely on man-made drainage systems. The state now formally recognizes these as “artificial drainage systems.”
These systems consist primarily of open channels, or drains, designed to collect and convey stormwater from one area to another—moving it away from homes, businesses, streets, and other developed areas. In our case, the ultimate goal is to move stormwater toward the arroyo.
Our drainage network is essentially a connected system of channels and laterals that work together to move stormwater throughout communities such as Harlingen, Combes, Palm Valley, and Primera and ultimately toward the arroyo.
However, these drainage channels are not flood-proof. Every channel has a maximum capacity. When rainfall produces more water than the system can handle, the channels can overflow. We experienced the consequences of that during major storm events in both 2019 and 2025.
That is why detention ponds have become an important part of our overall drainage strategy. Detention ponds provide a place to temporarily store excess stormwater when drainage channels are approaching or exceeding their capacity.
Rather than allowing excess water to spill out of the drainage system and potentially reach homes and businesses, a detention pond temporarily holds that water. As conditions improve and capacity becomes available within the drainage system, the stored water can then be released gradually.
Three Ways We Are Working to Reduce Flooding
Whether through partnerships with local cities, projects completed in-house, or securing state and federal grant funding, Cameron County Drainage District No. 5 is actively working in three key areas to improve drainage and reduce the risk of flooding in our extremely flat terrain:
1. Widening and Regrading Drainage Channels
Widening a channel increases its capacity to carry stormwater. Regrading restores the proper slope of the channel, allowing water to move through the system more efficiently. Together, these improvements increase the channel’s ability to carry stormwater and improve the overall performance of the drainage system.
2. Building Detention Ponds
Detention ponds temporarily hold excess stormwater and reduce the amount of water entering a drainage system at one time. Think of a detention pond as a temporary holding area. When a drainage channel is approaching its capacity, the pond provides additional storage rather than allowing excess water to spill into surrounding neighborhoods and businesses.
3. Upgrading Culverts and Crossings
Culverts are critical points in the drainage system where stormwater must pass underneath streets, roads, railroads, and other infrastructure. When a culvert is too small, damaged, clogged, or poorly designed, it can become a “bottleneck” in the drainage system.
It does not matter how large or efficient a drainage channel is if water cannot pass through a crossing fast enough. An inadequate culvert can cause water to back up, reducing the effectiveness of the drainage system and increasing the potential for flooding upstream.
By upgrading these crossings, we can increase the amount of stormwater that can pass through the system and help eliminate these bottlenecks.
The Bottom Line
Because we live on extremely flat terrain, we cannot simply rely on natural drainage to move stormwater away. We have to build, maintain, and continually improve the infrastructure that does that job for us.
That means improving our channels, creating additional storage through detention ponds, and removing bottlenecks by upgrading culverts and crossings.
No single project will eliminate flooding. But every improvement increases the capacity, efficiency, and resilience of the overall drainage system—and together, these projects help protect our homes, businesses, streets, and communities.
And if you’ve been following our recent posts, you’ve already seen some of that work underway—from the regrading and widening of drainage channels to the construction of our new 13-acre detention pond.
But there is much more to come.
Stay tuned for the multimillion-dollar drainage projects that the Cameron County Drainage District No. 5 Board of Directors is preparing to authorize for competitive bidding at its upcoming meeting.
These projects will include widening additional drainage channels and constructing new detention ponds—major investments designed to increase the capacity and efficiency of our drainage system and further reduce the risk of flooding in our communities.
We are continuing to invest in our drainage infrastructure—and we’re just getting started.
Stay tuned!
